HOLYOKE — City police continue to conduct street stops that result in drug arrests, according to Holyoke police records, which don't cite the alleged actions that precede such stops.

The stop-and-frisk tactics used by some U.S. police departments are a concern for the ACLU and other groups that advocate for civil liberties, including Massachusetts Cop Block, an organization that aims to promote police accountability in the Bay State. Cop Block has questioned what, specifically, triggers such stops, some of which end with people being arrested on drug and other charges.

"What is a 'street stop?' Are Holyoke police doing stop-and-frisk like the NYPD?" the organization asked in a tweet last week, following coverage by The Republican and MassLive.com of street stops leading to drug arrests.

Holyoke police officials were not immediately available Wednesday to discuss street stops, which have resulted in three drug arrests since Saturday and numerous other arrests in the past few months.

The tactic has become a hot-button issue across the country. In the nation's largest city, Mayor Michael Bloomberg has come under fire for stop-and-frisk tactics used by the New York Police Department. Bloomberg says the policing technique, used primarily to remove illegal firearms from city streets, saves lives. Fewer guns, he reasons, means fewer people who are likely to die from guns.

The ACLU and other groups see things differently, however, pointing to a perceived racial component to stop-and-frisk. About 85 percent of those stopped by police in New York are black or Hispanic, which suggests racial profiling by city police, they argue.

A federal trial claiming stop-and-frisk violates the Fourth Amendment's protection against unreasonable searches and the Fourteenth Amendment's equal protection clause concluded last month in New York, but a ruling isn't expected for months.

During the trial, Judge Shira A. Scheindlin questioned the efficacy and "high error rate" of street stops, only about 12 percent of which lead to an arrest or summons. That means the "reasonable suspicion" used by officers to stop and search potential suspects is wrong about 88 percent of the time, she said. "You reasonably suspect something and you're wrong (nearly) 90 percent of the time," Scheindlin said.

Terry V. Ohio is the 1968 U.S. Supreme Court ruling that lowered the criminal standard for performing street stops, which went from requiring police officers to have "probable cause" to needing only "reasonable suspicion."

Some experts argue that today's emergency-room physicians are better at treating trauma patients than ever before, helping to drive down homicide rates in big cities like New York. Sociologist Anthony Harris, a professor at UMass-Amherst, says the reduction in Big Apple homicides – from a record 2,245 murders in 1990 to 414 last year – has more to do with developments in trauma care than stop-and-frisk tactics by officers on the beat.